I wish to understand interesting behaviour developing in my tank. Is it courtship or male dominance? This pair are also chasing the other Beckfordi.
Also, can anyone ID the algae sprouting from the bogwood? It first appeared several months ago and all my research has proved futile!

@BigTom said:
Cool algae! Some sort of Thorea species would be my guess, seems to crop up from time to time in the hobby although not common. Possibly T. hispida? http://www.aquamax.de/index.php/neue-rotalgen.html

Interesting thing is it only appears on the bogwood, not on the plants.

They are in almost constant persuit of each other and chase the other Beckfordi about.

I added 4 Beckfordi juveniles to the tank two weeks ago, to add to the three I had to bolster their numbers. Within 48 hours the drama unfolded and shows no sign of resolving. Now I am very pleased to see the exhibition of natural behaviour, however I read that what we call “male displaying” in a closed system can lead ultimately to the death of one of the competing males. I’m thinking of returning one of the males to my lfs. Am I overreacting?

First, this behaviour actually has nothing to do with females. It is display/dominance between males, and will occur whether female fish are in the tank or not. I have had this species several times over 20 years, and my current group of ten were purchased when they were very small and male/female was not noticeable in the store tank (fish are not only small, but generally less than happy with the bare tank and washed out in colour). As luck would have it, I ended up with all males. I’ve had them for almost a year now, and haven’t been able to find them since to add more. Anyway, the males carry on like this continually. Most often in pairs, but I have several times seen three in a line. To the fish is it perhaps more serious than “play,” but damage to each other is very rare; I have read it can occur, but in my experience I have never seen actual physical damage result.

To your group, I would add a few more; seven is a nice number, but another 3-5 would be even better. If you can, try to get a mix of male/female as the males can drive females rather hard.

Also, floating plants should always be included. This species, like most pencilfish (which are currently all in the genus Nannostomus following Weitzman’s classification), remain in the upper third of the water column and like to spend time among floating vegetation with dangling roots. They browse the leaves and roots for microscopic bits of food. They also spawn among the floating plants. Some fry might survive with a thick enough cover of floating plants, depending upon other fish in the aquarium; I have had this a couple times in the past.

There is one downside to this species. It is the only one of all the pencils, in my experience to date, that can be a bit nippy with other fish, especially those near the surface. Hatchetfish for example. The male beckfordi seem to have “territories” and will defend them. I suspect this is not territory in the sense of cichlids and spawning, but just what they see as “their space” for feeding. It is variable, so whatever space suits the male at the moment, becomes “his.” Another fish that can get picked on a bit is the Otocinclus; when one of mine lands on a leaf in one of these “spaces,” it is usually driven off fast. My beckfordi and otos are in a 5-foot 115g tank, so this has caused no problems as the otos simply move off to another leaf.